Method and system for detection of weighted contact lenses imprinted with iris images

ABSTRACT

Disclosed herein are methods, apparatus, and systems for iris recognition. A method for weighted spoof contact lens detection includes requesting a subject to roll or tilt head when needing access via an iris recognition device, acquiring, by the iris recognition device, iris images of a rolled head, establishing, by the iris recognition device, a horizontal axis by connecting pupils in an iris image, matching, by the iris recognition device, at least one iris in the iris image to an enrolled iris, determining, by the iris recognition device, whether the horizontal axis is within a rotational variance of an enrolled horizontal axis associated with the enrolled iris, and rejecting, by the iris recognition device, access for the subject when the horizontal axis is greater than the rotational variance of an enrolled horizontal axis.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 63/106,931, filed Oct. 29, 2020, the entiredisclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates to iris recognition. More specifically, thisdisclosure relates to detecting iris imprinted, spoofing weightedcontact lenses.

BACKGROUND

Individuals can be recognized using a variety of biometric methods,e.g., face, fingerprint, and irises. Some of these biometric methods,such as fingerprint recognition methods, require individuals to touch orcontact the biometric recognition device. This can be difficult for someindividuals or during periods where users of such biometric recognitionsystems do not want to touch any surfaces that might have beencontaminated by other individuals. Consequently, the use of suchbiometric recognition systems are shunned.

Biometric recognition systems including iris recognition systems aresubject to attempts to spoof the system. These spoofing attempts willincrease as the number of valuable resources protected by irisrecognition systems increases. A nightmare scenario for iris recognitionfeatures a nefarious subject wearing contact lenses that reliablyidentify them as a different person. Therefore, a means to detect suchan attack vector is essential to protect high value resources that useiris recognition access control systems.

SUMMARY

Disclosed herein are methods, apparatus, and systems for irisrecognition.

In implementations, a method for weighted spoof contact lens detectionincludes requesting a subject to roll or tilt head when needing accessvia an iris recognition device, acquiring, by the iris recognitiondevice, iris images of a rolled head, establishing, by the irisrecognition device, a horizontal axis by connecting pupils in an irisimage, matching, by the iris recognition device, at least one iris inthe iris image to an enrolled iris, determining, by the iris recognitiondevice, whether the horizontal axis is within a rotational variance ofan enrolled horizontal axis associated with the enrolled iris, andrejecting, by the iris recognition device, access for the subject whenthe horizontal axis is greater than the rotational variance of anenrolled horizontal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detaileddescription when read in conjunction with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not to scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.

FIG. 1A-1C are diagrams of an example subject with weighted irispatterned contact lenses.

FIG. 2 is a diagram of an example architecture for iris recognition inaccordance with implementations of this disclosure.

FIG. 3 is a diagram of an example access control system with an exampleiris recognition device in accordance with implementations of thisdisclosure.

FIG. 4 is a diagram of an example iris recognition server for use withthe access control system of FIG. 3 in accordance with implementationsof this disclosure.

FIG. 5 is a diagram of an example configuration of an iris recognitiondevice in accordance with implementations of this disclosure.

FIG. 6A-6E are diagrams of an example subject with enrolled iristemplates and another subject with weighted iris patterned contactlenses.

FIG. 7 is a block diagram of an example of a device in accordance withimplementations of this disclosure.

FIG. 8 is a flowchart of an example method for detecting a spoof contactlens in accordance with implementations of this disclosure.

FIG. 9 is a diagram of example method for detecting a spoof contact lensin accordance with implementations of this disclosure.

DETAILED DESCRIPTION

Reference will now be made in greater detail to embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals will be usedthroughout the drawings and the description to refer to the same or likeparts.

As used herein, the terminology “computer” or “computing device”includes any unit, or combination of units, capable of performing anymethod, or any portion or portions thereof, disclosed herein. Forexample, the “computer” or “computing device” may include at least oneor more processor(s).

As used herein, the terminology “processor” indicates one or moreprocessors, such as one or more special purpose processors, one or moredigital signal processors, one or more microprocessors, one or morecontrollers, one or more microcontrollers, one or more applicationprocessors, one or more central processing units (CPU)s, one or moregraphics processing units (GPU)s, one or more digital signal processors(DSP)s, one or more application specific integrated circuits (ASIC)s,one or more application specific standard products, one or more fieldprogrammable gate arrays, any other type or combination of integratedcircuits, one or more state machines, or any combination thereof.

As used herein, the terminology “memory” indicates any computer-usableor computer-readable medium or device that can tangibly contain, store,communicate, or transport any signal or information that may be used byor in connection with any processor. For example, a memory may be one ormore read-only memories (ROM), one or more random access memories (RAM),one or more registers, low power double data rate (LPDDR) memories, oneor more cache memories, one or more semiconductor memory devices, one ormore magnetic media, one or more optical media, one or moremagneto-optical media, or any combination thereof.

As used herein, the terminology “instructions” may include directions orexpressions for performing any method, or any portion or portionsthereof, disclosed herein, and may be realized in hardware, software, orany combination thereof. For example, instructions may be implemented asinformation, such as a computer program, stored in memory that may beexecuted by a processor to perform any of the respective methods,algorithms, aspects, or combinations thereof, as described herein.Instructions, or a portion thereof, may be implemented as a specialpurpose processor, or circuitry, that may include specialized hardwarefor carrying out any of the methods, algorithms, aspects, orcombinations thereof, as described herein. In some implementations,portions of the instructions may be distributed across multipleprocessors on a single device, on multiple devices, which maycommunicate directly or across a network such as a local area network, awide area network, the Internet, or a combination thereof.

As used herein, the term “application” refers generally to a unit ofexecutable software that implements or performs one or more functions,tasks or activities. For example, applications may perform one or morefunctions including, but not limited to, telephony, web browsers,e-commerce transactions, media players, travel scheduling andmanagement, smart home management, entertainment, and the like. The unitof executable software generally runs in a predetermined environmentand/or a processor.

As used herein, the terminology “determine” and “identify,” or anyvariations thereof includes selecting, ascertaining, computing, lookingup, receiving, determining, establishing, obtaining, or otherwiseidentifying or determining in any manner whatsoever using one or more ofthe devices and methods are shown and described herein.

As used herein, the terminology “example,” “the embodiment,”“implementation,” “aspect,” “feature,” or “element” indicates serving asan example, instance, or illustration. Unless expressly indicated, anyexample, embodiment, implementation, aspect, feature, or element isindependent of each other example, embodiment, implementation, aspect,feature, or element and may be used in combination with any otherexample, embodiment, implementation, aspect, feature, or element.

As used herein, the terminology “or” is intended to mean an inclusive“or” rather than an exclusive “or.” That is unless specified otherwise,or clear from context, “X includes A or B” is intended to indicate anyof the natural inclusive permutations. That is if X includes A; Xincludes B; or X includes both A and B, then “X includes A or B” issatisfied under any of the foregoing instances. In addition, thearticles “a” and “an” as used in this application and the appendedclaims should generally be construed to mean “one or more” unlessspecified otherwise or clear from the context to be directed to asingular form.

Further, for simplicity of explanation, although the figures anddescriptions herein may include sequences or series of steps or stages,elements of the methods disclosed herein may occur in various orders orconcurrently. Additionally, elements of the methods disclosed herein mayoccur with other elements not explicitly presented and described herein.Furthermore, not all elements of the methods described herein may berequired to implement a method in accordance with this disclosure.Although aspects, features, and elements are described herein inparticular combinations, each aspect, feature, or element may be usedindependently or in various combinations with or without other aspects,features, and elements.

Further, the figures and descriptions provided herein may be simplifiedto illustrate aspects of the described embodiments that are relevant fora clear understanding of the herein disclosed processes, machines,manufactures, and/or compositions of matter, while eliminating for thepurpose of clarity other aspects that may be found in typical similardevices, systems, compositions and methods. Those of ordinary skill maythus recognize that other elements and/or steps may be desirable ornecessary to implement the devices, systems, compositions and methodsdescribed herein. However, because such elements and steps are wellknown in the art, and because they do not facilitate a betterunderstanding of the disclosed embodiments, a discussion of suchelements and steps may not be provided herein. However, the presentdisclosure is deemed to inherently include all such elements,variations, and modifications to the described aspects that would beknown to those of ordinary skill in the pertinent art in light of thediscussion herein.

Techniques prior to those described herein for detecting spoof contactlenses suffer from detectability issues. For example, the detection ofcontact lenses can rely on detection of the subtle circular line definedby the edge of the contact lens that appears just beyond the subject'siris on the sclera. This faint line is difficult to see in the eyes ofsome subject subjects. And even if detected, a contact lens can be abenign means of correcting vision so merely detecting a contact lensdoesn't distinguish ‘good’ from ‘bad’ lenses. Detection of contactlenses can also use printing artifacts to identify a spoof such as thedot-matrix array of applied coloration on the lens. However, as contactlens patterning improves, the appearance of such dots has become moredifficult to detect. And while cosmetic patterned contact lenses areincompatible with iris detection systems, they are not the nefariousspoof represented by iris pattern imprinted lenses.

Described herein are methods and systems for detecting weighted, irisprinted contact lenses. The methods and systems detect spoof contactlenses by using the weighting that fixes the rotational position of thelens on the cornea to correct astigmatism. In implementations, themethod detects any patterned contact lens that uses gravity to remainpersistently aligned with the subject's eyes and face in a verticalorientation. The methods described herein rely on neither detecting acontact lens edge nor printing artifacts but instead measures therotational orientation of the iris pattern when the subject rotatestheir head away from the position for which the spoof contact lenseswere designed assuming that the lens rotates due to gravitational force.

In implementations, the methods can use existing and well-establishediris recognition methods to establish the rotational position of eachiris. For example, the most widely used iris recognition algorithmincludes a step to measure the rotational position of the iris. Becauseiris-patterned spoof contact lenses must be weighted to remainrotationally oriented (unless they are attached to the cornea by amedically impractical and risky method), the described methods exposespoof contact lenses by rotationally reorienting them.

These relationships are shown with respect to FIGS. 1A-1C, which arediagrams of an example subject 1000 with weighted iris patterned contactlenses 1100. Weighted contact lenses are generally worn to addressastigmatism. FIG. 1A is a diagram of the subject 1000 wearing theweighted iris patterned contact lenses 1100. In this instance, a head1200, face 1300, and an iris and/or iris texture (denoted as R for righteye and L for left eye) 1400 are in a vertical position. Dashed line1500 represents horizontal axes with respect to the face 1300 thatconnect right and left pupils 1600. FIG. 1B is a diagram of the subject1000 captured immediately after rolling the head 1200 in one direction.As shown, the head 1200, the face 1300, and the iris and/or iris texture1400, and a dashed line 1700 are all tilted. FIG. 1C is a diagram of thesubject 1000 captured sometime after rolling the head 1200 in onedirection. As shown, the head 1200, the face 1300, and a dashed line1800 are all tilted. However, the iris and/or iris texture 1400 isvertical because the weighted iris patterned contact lenses 1100 havereoriented under the force of gravity. Detection of the FIG. 1Corientation after detection of the FIG. 1B orientation after a definedtime period determines the presence of spoof weighted contact lenses.

It is noted that a real iris pattern of an eye is fixed in itsrotational position relative to a subject's face. In other words, afreckle on the edge of an iris that is positioned at 12 o'clock when asubject's face is vertically oriented rotates along with the rest of theiris pattern by 90° when the subject rolls their head by 90°. Thus, tobe successful, a spoof iris pattern on an iris-patterned contact lensmust rotate exactly as a natural iris rotates. Otherwise, it can bedistinguished as a spoof iris. In addition, a contact lens spoofimprinted with a realistic iris pattern must persist in the rotationalorientation of the iris pattern that it is spoofing. For contact lenses,this means that the lens must be weighted to maintain stable rotationalorientation (assuming that the lens cannot be safely fixed to the corneaof the user). This collectively creates a problem for a spoof contactlens since the contact lens must rotate with the user's face (and remainaligned with the face orientation) when a user rotates their head andthe weight that uses gravity to maintain the alignment of a spoofcontact lens will force the lens to drift unnaturally when the user'shead is rotated (rolled) from a vertical position.

It is noted that commercially available contact lenses already boast oftheir ability to remain aligned with a vertically oriented face.CooperVisions's Biofinity® toric and XR toric lenses as well asAcuvue's® Oasys contact lenses use systems of weighting to “quicklyorient the lens for better performance”, that is, to maintain rotationalorientation of the contact lenses used to correct astigmatism. On theeyes of a subject whose head is oriented vertically, the weight on eachcontact lens “iris stabilizes” the lens on the cornea so that it orientsdue to the pull of gravity following blinks and sudden eye motion. Indoing so, the rotationally dependent astigmatic correction properlyaligns with the subject's eye if the user's head is vertical. Asimilarly weighted spoof contact lens would orient properly relative togravity on the eye of a nefarious subject who might successfully spoofan iris recognition system that simply requires presentation with auser's head oriented vertically.

However, if the subject rolls their head to one side or the other, sayby 30° and then pauses while gravity reorients the rotationalorientation of their contact lenses, the rotational position of thespoof contact lens will no longer be correctly oriented relative to thesubject's face. Operationally, the reoriented iris patterns would nolonger align with an axis connecting the subject's two pupils which isfixed relative to the subject's face. Consequently, an iris recognitionsystem needs to examine the rotational position of the irises on thesubject with head rolled to one side to detect weighted contact lenses.And since weighting is necessary to maintain the orientation ofiris-patterned spoof contact lenses through the day, head-rolling is ameans to expose this sophisticated spoof. In implementations, likelihoodof detecting iris-patterned spoof contact lenses can be increased bycomparing the rotational position of each of two irises to correspondingenrolled reference irises or comparing the rotational position of eachof two iris-patterned to one another after a subject rolls their head toone side and waits for gravity to reorient spoof contact lenses. Each ofthe methods operate with respect to iris-patterned spoof contact lensesthat are weighted and wait for gravity to rotationally reorient thespoof contact lenses on the rolled head of a subject after a reasonablyshort time.

FIG. 2 is a diagram of an example architecture or system 2000 for irisrecognition in accordance with implementations of this disclosure. Inimplementations, the architecture or system 2000 can be deployed,provided, or implemented in warehouses, offices, buildings, residences,hospitals, nursing homes, rehabilitation centers, vaults, airports,concerts, and other facilities or events. In implementations, thearchitecture 2000 can include a room or building 2100, which is accessedby a user 2200 via a door 2300. The door 2300 is illustrative of anaccess controlled facility, object, and the like (collectively “accesscontrolled entity”). The door 2300 can be opened or unlocked by anaccess control system 2400. In implementations, the access controlsystem 2400 includes an iris recognition device 2410 and an accesscontrol module 2420. In implementations, the access control system 2400includes the iris recognition device 2410, the access control module2420, and an iris recognition server 2430. In implementations, theaccess control system 2400 includes the iris recognition device 2410,the access control module 2420 and an access control center 2440. Inimplementations, the access control system 2400 includes the irisrecognition device 2410, the access control module 2420, the irisrecognition server 2430, and the access control center 2440. Inimplementations, the iris recognition device 2410, the access controlmodule 2420, the iris recognition server 2430, and the access controlcenter 2440, as appropriate and applicable, are connected or incommunication (collectively “connected”) using a network 2500. Thearchitecture 2000 may include other elements, which may be desirable ornecessary to implement the devices, systems, compositions and methodsdescribed herein. However, because such elements and steps are wellknown in the art, and because they do not facilitate a betterunderstanding of the disclosed embodiments, a discussion of suchelements and steps may not be provided herein.

The iris recognition device 2410 is a touchless and contactless devicefor recognizing a user. The iris recognition device 2410 captures one ormore images of the user 2000. The one or more images include an eyecomprising an iris and a pupil. The iris recognition device 2410 candetermine if the user 2000 is wearing weighted, iris printed contactslenses in an attempt to spoof the iris recognition device 2410 asdescribed herein. An alarm signal is generated if a spoof is detected.The iris recognition device 2410 can signal the access control module2420, the access control center 2440, the iris recognition server 2430,or combinations thereof. The iris recognition device 2410 can generateiris templates if the iris recognition device 2410 determines it is nota spoof. The iris templates are matched against enrolled iris templatesto determine if the user 2000 has access. An access signal is generatedbased on the results of the matching. In an implementation, the irisrecognition device 2410 is a standalone device. In an implementation,the iris recognition device 2410 can communicate with the irisrecognition server 2430 and the access control center 2440 tocollectively determine access based on the matching results.

The access control module 2420 can receive the access signal from theiris recognition device 2410. The access control module 2420 can open orunlock the door 2300 based on the access signal. In implementations, theaccess control module 2420 can send a signal to a lock/unlock device(not shown) on the door 2300 to open or unlock. In implementations, theaccess control module 2420 can receive the access signal from the accesscontrol center 2440. In implementations, the access control module 2420can receive the access signal from the iris biometric recognition server2430. In implementations, the access control module 2420 can receive theaccess signal from a combination of the iris recognition device 2410,the iris recognition server 2430, and the access control center 2440. Inimplementations, the access control module 2420 can receive an alarmsignal from the iris recognition device 2410, the access control center2440, the iris recognition server 2430, or combinations thereof. Inimplementations, the access control module 2420 can generate an alarmbased on the alarm signal. The alarm can be a light, an audible alarm, asilent alarm, and the like. In implementations, the access controlmodule 2420 is integrated with the iris recognition device 2410. Inimplementations, the access control module 2420 is integrated with thedoor 2300. In implementations, the access control module 2420 is astandalone device in communication with the iris recognition device2410, the door 2300, the iris recognition server 2430, the accesscontrol center 2440, or combinations thereof.

The iris recognition server 2430 can receive captured images from theiris recognition device 2410. The iris recognition server 2430 canperform iris recognition as described herein for the iris recognitiondevice 2410. The iris recognition server 2430 can communicate alarms andresults to the iris recognition device 2410, the access control module2420, the access control center 2440, or combinations thereof.

The access control center 2440 can be smart monitors, smartphones,computers, desktop computers, handheld computers, personal mediadevices, notebooks, notepads, tablets, and the like which cancommunicate between the iris recognition device 2410, the access controlmodule 2420, the iris recognition server 2430, or combinations thereof.The access control center 2440 can review the results from the matchingby the iris recognition device 2410, the iris recognition server 2430,or combinations thereof to determine what access signal should be sentto the access control module 2420. In implementations, the accesscontrol center 2440 can receive an alarm signal from the irisrecognition device 2410, the iris recognition server 2430, the accesscontrol module 2420, or combinations thereof. In implementations, theaccess control center 2440 can generate an alarm based on the alarmsignal. The alarm can be a light, an audible alarm, a silent alarm, andthe like.

The network 2500 may be, but is not limited to, the Internet, anintranet, a low power wide area network (LPWAN), a local area network(LAN), a wide area network (WAN), a public network, a private network, acellular network, a WiFi-based network, a telephone network, a landlinenetwork, public switched telephone network (PSTN), a wireless network, awired network, a private branch exchange (PBX), an Integrated ServicesDigital Network (ISDN), a IP Multimedia Services (IMS) network, a Voiceover Internet Protocol (VoIP) network, and the like including anycombinations thereof.

FIG. 3 is a diagram of an example access control system 3000 with anexample iris recognition device 3100 in accordance with implementationsof this disclosure. The access control system 3000 can include the irisrecognition device 3100 in communication with an access control module3200. The iris recognition device 3100 can include an iris recognitionmodule 3110, a reference database 3120, a detection module 3130, one ormore image capturing device(s) 3140, one or more illuminator(s) 3150,and a controller 3160. In implementations, the iris recognition device3100 can include an iris enrollment system 3170. In implementations, theiris recognition device 3100 and the access control module 3200 can bean integrated device. In implementations, the iris recognition device3100 and the access control module 3200 can be connected standalonedevices. The access control system 3000 may include other elements,which may be desirable or necessary to implement the devices, systems,compositions and methods described herein. However, because suchelements and steps are well known in the art, and because they do notfacilitate a better understanding of the disclosed embodiments, adiscussion of such elements and steps may not be provided herein.

The detection module 3130 can be a motion sensor, a proximity sensor,and like device which can determine the presence of an individual orwhether an individual is proximate to an access controlled entity. Thedetection module 3130 can awaken or signal the access control system3000, the iris recognition device 3100, or combinations thereof of thepresence of the individual. In implementations, the access controlsystem 3000 can be in a low power mode or on persistently to performscanning. Activation of the access control system 3000 occurs when thescanning finds a scannable object.

The one or more image capturing device(s) 3140 can be a camera, animager, or like device for capturing one or more images of theindividual. In implementations, the one or more image capturingdevice(s) 4140 is a near infrared image capturing device, a visibleimage capturing device, or combinations thereof.

The one or more illuminator(s) 3150 can be one or more light sources,light emitting diodes, and the like which can illuminate the individualin coordination with capturing an image of the individual. Inimplementations, the one or more illuminator(s) 3150 can be visiblelight sources including ambient light, visible light emitting diodes(LEDs), near infrared light sources including ambient light, nearinfrared light emitting diodes (LEDs), and the like.

The iris recognition module 3110 can perform iris recognition on thecaptured images as described herein. In implementations, the irisrecognition module 3110 determines if a spoof contact lens is being usedand if not, generates appropriate or applicable iris templates,representations, or the like, and matches the iris templates to enrolledtemplates stored in the reference database 3120. The iris recognitionmodule 3110 can send matching results to the access control module 3200.In implementations, the results can be scores, a decision, orcombinations thereof. If a spoof is detected, an alarm can be generatedor an alarm signal can be sent as described herein.

The reference database 3120 can include iris templates, and other liketemplates for individuals enrolled in the access control system 3000.

The controller 3160 can control and coordinate the operation of thedetection module 3130, the one or more image capturing device 3140, theone or more illuminator(s) 3150, and if applicable, the iris enrollmentsystem 3170.

The iris enrollment system 3170 can enroll individuals into the accesscontrol system 3000. The one or more image capturing device(s) 3140 andthe one or more illuminator(s) 3150 can capture images of individualswhich are processed by the iris recognition module 3110 to generate iristemplates. The iris templates can then be stored in the referencedatabase 3120 for matching analysis by the iris recognition module 3110.

The access control module 3200 can receive matching results from theiris recognition device 3100. If a positive match occurs, the accesscontrol module 3200 can open or unlock the access controlled entity forthe individual or send a signal to the access controlled entity, whichin turn can cause the access controlled entity to open or unlock. Inimplementations, the access control module 3200 can access othersecurity systems to determine security, access, authorization levels orthe like for a matched individual. That is, the iris recognition is oneof multiple steps in providing access to a secured asset. The accesscontrol module 3200 can receive alarm signals as described herein andprocess accordingly.

FIG. 4 is a diagram of an example iris recognition server for use withthe access control system of FIG. 3 in accordance with implementationsof this disclosure. The iris recognition server 4000 can include an irisrecognition module 4100, a reference database 4200, a controller 4300,and an iris enrollment system 4400. The iris recognition server 4000 mayinclude other elements which may be desirable or necessary to implementthe devices, systems, compositions and methods described herein.However, because such elements and steps are well known in the art, andbecause they do not facilitate a better understanding of the disclosedembodiments, a discussion of such elements and steps may not be providedherein.

The iris recognition server 4000 can communicate with the access controlsystem 3000, the iris recognition device 3100, the access control module4200, and combinations thereof via a network such as network 2500. Theiris recognition module 4100 can operate as described for irisrecognition module 3110. The reference database 4200 can operate asdescribed herein for the reference database 3120. The controller 4300can control and coordinate the operation of the iris recognition device3100, the access control module 3200, the iris recognition module 4100,the reference database 4200, the iris enrollment system 4400, andcombinations thereof.

FIG. 5 is a diagram of an example iris recognition module 5000 inaccordance with implementations of this disclosure. In implementations,the iris recognition module 5000 is the iris recognition module 3110 inFIG. 3 and the iris recognition module 4100 in FIG. 4. The irisrecognition module 5000 can include an eye finder 5100, an iris findermodule 5200, an iris encoder module 5300, and an iris matcher module5400.

The iris recognition module 5000 can process two types of images,straight head image(s) and when appropriate, tilted or rolled headimage(s). In implementations, when the straight analysis is successful,the user or subject can be asked to tilt or roll their head to one sideby ΔθROLL, e.g., 30° (rotating about an axis running from front to back)for a defined interval Δτ, e.g. 10 to 30 seconds. For example, this isshown in FIG. 1B. In this instance, the user can be asked to keep theireyes open for a substantial portion of the defined interval. The definedinterval permits any weighted spoof contact lenses to reorient on thesubject's eyes.

The eye finder module 5100 can locate or find one or more eyes of asubject in the straight image(s) that contains at least an appropriateportion of a face of the subject using conventional techniques. Anappropriate portion can refer to having on or more landmarks todetermine the one or more eyes of the subject. The eye finder module5100 can determine or establish a horizontal axis (or first horizontalaxis when appropriate) relative to the subject's face, e.g., using aline through the center of each pupil. For example, this is shown inFIG. 1A as dashed line 1500. In implementations, the eye finder module5100 can locate one or more eyes of a subject in the tilted image(s)that contains at least an appropriate portion of a face of the subjectusing conventional techniques. The eye finder module 5100 can determineor establish a second horizontal axis relative to the subject's face,e.g., using a line through the center of each pupil. For example, thisis shown in FIG. 1C as dashed line 1800.

The iris finder module 5200 can operate on or process the located eyesfor the straight head image to find the iris(es) using conventionaltechniques. The iris finder module 5200 segments the iris from the pupilusing conventional techniques. In implementations, the iris findermodule 5200 can operate on or process the located eyes for the tiltedhead image to find the iris(es) using conventional techniques. The irisfinder module 5200 segments the iris from the pupil using conventionaltechniques.

The iris encoder module 5300 can encode the segmented iris relative tothe horizontal axis for the straight head image using conventionaltechniques. The iris encoder module 5300 can generate a straight headdigitized iris template from the encoded iris. In implementations, theiris encoder module 5300 can encode the segmented iris relative to thesecond horizontal axis for the tilted head image using conventionaltechniques.

The iris matcher module 5400 can compare the iris template(s) againstiris enrolled templates and provide iris match scores. The iris matchermodule 5400 can check that the iris patterns match to enrolled irisimages and that the rotational orientation of the iris images match therotational orientation of enrolled iris images (relative to the facehorizontal axis) to within a given angular tolerance ΔθTOL, e.g., ±10degrees, and if not, reject the subject. In implementations, when thestraight head analysis is successful, the iris matcher module 5400 cancompare the rotational position of the tilted head iris images (relativeto the second horizontal axis) to the rotational position of enrolledirises or to the rotational position of straight up iris images(relative to the nominally level, first horizontal axis) to detectunnatural rotation of the iris patterns on the subject's eyes. The irismatcher module 5400 can reject the subject and generate an alarm ifunnatural rotation is detected or can accept the subject as legitimatelyrecognized.

An operational discussion of FIGS. 1-5 is described with respect toFIGS. 6A-6E, which are diagrams of an example subject with enrolled iristemplates and another subject with weighted iris patterned contactlenses to spoof the subject. FIG. 6A are diagrams of enrolled irisimages 6000 of right and left eyes. FIG. 6B are diagrams of iris images6100 of a subject without spoof contacts immediately after head roll.FIG. 6C are diagrams of iris images 6200 of a subject without spoofcontacts after a time interval defined interval Δτ. FIG. 6D are diagramsof iris images 6300 of a subject with spoof contact lenses immediatelyafter head roll. FIG. 6E are diagrams of iris images 6400 of a subjectwith spoof contact lenses after the defined interval Δτ. Iris images areshown relative to a horizontal axis (6010, 6110, 6210, 6310, and 6410)(dashed line) relative to the face (6020, 6120, 6220, 6320, and 6420)that connects right and left pupils (6030,6032, 6130,6132, 6230,6232,6330,6332, and 6430,6432). Note that the rotational orientation of Ematches neither FIG. 6A (enrolled) nor FIG. 6D (immediately after headroll) as described herein.

Operationally, with reference to FIGS. 1-6E, an individual 2200self-aligns to a camera configuration as described herein in an irisrecognition device. The camera(s), in conjunction with theilluminator(s) can produce an image or set of images of the individual2200. Each captured image or frame is submitted for eye locationdetermination as performed by the eye finder module 5100, for example.The eye finder module 5100 can establish a horizontal axis relative tothe subject's face (can be referred to as first horizontal axis whenappropriate), e.g., using a line through the center of each pupil.Conventional iris pattern analysis can be applied to the iris images toencode each iris relative to the determined horizontal line. Irismatching can be performed against enrolled iris images such as the irisimages 6000 shown in FIG. 6A and to check the rotational orientation ofthe iris images against the rotational orientation of matched, enrollediris images (relative to the face horizontal axis) to within a givenangular tolerance ΔθTOL, e.g., ±10 degrees. If the iris pattern does notmatch, or the rotation orientation is greater than the angular toleranceΔθTOL, then the subject is rejected and an alarm can be generated.

In the event of a successful iris match and acceptable rotationorientation, then the subject can be asked to perform a head roll. Forexample, the subject can be asked to roll their head to one side byΔθROLL, e.g., 30° (rotating about an axis running from front to back)for a defined interval Δτ, e.g. 10 to 30 seconds with the subjectkeeping their eyes open for a substantial portion of the time. Thedefined interval Δτ permits weighted spoof contact lenses, if beingworn, to reorient on the subject's eyes.

The head roll images can be processed similarly as above. That is, theeyes can be located in the head roll images and a second horizontal axiscan be determined relative to the subject's face with head rolled.Conventional iris pattern analysis can be applied to head roll irisimages to encode each iris relative to the determined second horizontalline.

Head roll iris images can be matched against enrolled iris images andthe rotational position of head roll iris images (relative to the secondhorizontal axis) can be compared to the rotational position of enrolledirises, e.g., FIG. 6A versus FIG. 6E, or to the rotational position ofthe successfully matched iris images (relative to the nominally level,first horizontal axis) to detect unnatural rotation of the iris patternson the subject's eyes, e.g., FIG. 6D versus 6E. Images are beingcontinuously captured or acquired. If unnatural rotation is detected(either FIG. 6A versus FIG. 6E or FIG. 6D vs. 6E), then the irisrecognition device can reject the subject, otherwise the irisrecognition device can accept the subject as legitimately recognized,e.g., either FIG. 6A versus FIG. 6C or FIG. 6A versus FIG. 6B. In thisinstance, an image(s) is captured immediately after the head roll andanother image(s) is captured after a period of time. These images areprocessed as described herein for purposes of detecting weighted spoofcontact lenses. The period of time enables a temporal aspect forweighted contact lenses, if present, to settle due to gravity.

FIG. 7 is a block diagram of an example of a device 7000 in accordancewith embodiments of this disclosure. The device 7000 may include, but isnot limited to, a processor 7100, a memory/storage 7200, a communicationinterface 7300, and applications 7400. The device 7000 may include orimplement, for example, the access control system 2400, the irisrecognition device 2410, the access control module 2420, the irisrecognition server 2430, the access control center 2440, the accesscontrol system 3000, the iris recognition device 3100, the accesscontrol module 3200, the iris recognition module 3110, the referencedatabase 3120, the detection module 3130, the one or more imagecapturing device(s) 3140, the one or more illuminator(s) 3150, thecontroller 3160, the iris enrollment system 3170, the iris recognitionserver 4000, the iris recognition module 4100, the reference database4200, the controller 4300, the iris enrollment system 4400, the irisrecognition module 5000, the eye finder module 5100 the iris findermodule 5200, the iris encoder module 5300, and the iris matcher module5400, for example. In an implementation, appropriate memory/storage 7200may store the image(s), the iris information, the iris template(s), irismatch scores, and the list of matched scores. In an implementation,appropriate memory/storage 7200 is encoded with instructions for atleast iris recognition and access control. The iris recognitiontechniques or methods described herein may be stored in appropriatememory/storage 7200 and executed by the appropriate processor 7100 incooperation with the memory/storage 7200, the communications interface7300, and applications 7400, as appropriate. The device 7000 may includeother elements which may be desirable or necessary to implement thedevices, systems, compositions and methods described herein. However,because such elements and steps are well known in the art, and becausethey do not facilitate a better understanding of the disclosedembodiments, a discussion of such elements and steps may not be providedherein.

FIG. 8 is a flowchart of an example method 8000 for detecting a weightedspoof contact lens in accordance with implementations of thisdisclosure. The method 8000 includes: acquiring 8100 iris images;establishing 8200 horizontal axis for an iris image; for first pass,matching 8300 irises to enrolled irises including rotational variance,and for second pass, matching 8300 irises to enrolled irises and/oririses from first pass including rotational variance; when no match8400, rejecting 8500 subject; and for first pass, when yes 8600,requesting 8700 subject to perform head roll for a defined time 8800 andreturn to image acquisition 8900, and for second pass, when yes 8600accept subject. The method 8000 can be implemented using at least one ofthe access control system 2400, the iris recognition device 2410, theaccess control module 2420, the iris recognition server 2430, the accesscontrol center 2440, the access control system 3000, the irisrecognition device 3100, the access control module 3200, the irisrecognition module 3110, the reference database 3120, the detectionmodule 3130, the one or more image capturing device(s) 3140, the one ormore illuminator(s) 3150, the controller 3160, the iris enrollmentsystem 3170, the iris recognition server 4000, the iris recognitionmodule 4100, the reference database 4200, the controller 4300, the irisenrollment system 4400, the iris recognition module 5000, the eye findermodule 5100 the iris finder module 5200, the iris encoder module 5300,the iris matcher module 5400, the device 7000, the processor 7100, thememory/storage 7200, the communication interface 7300, and theapplications 7400, for example.

The method 8000 includes acquiring 8100 iris images. Iris images areacquired or captured from a subject with a head in a straight aheadposition (first pass). In implementations, when the straight aheadirises match, iris images are acquired or captured from the subject withthe head in a tilted or rolled position (second pass). Image(s) arecaptured immediately after the head roll and after a period of time. Theperiod of time provides the weighted contact lenses, if present, tosettle due to gravity. These images are processed as described hereinfor purposes of detecting weighted spoof contact lenses.

The method 8000 includes establishing 8200 horizontal axis for an irisimage. A horizontal axis is determined using the pupils in the irisimages.

The method 8000 includes a for first pass, matching 8300 irises toenrolled irises including rotational variance, and for a second pass,matching 8300 irises to enrolled irises and/or irises from first passincluding rotational variance. The straight ahead irises (first pass)are matched against enrolled irises to determine an iris match. Thisincludes determining whether the irises are within a rotationalvariance. In implementations, the head rolled irises (second pass) arecompared against the enrolled irises and/or the straight ahead irisesfrom the first pass to determine an iris match. This includesdetermining whether the irises are within a rotational variance.Rotational variances are determined by using a horizontal axis of theenrolled iris, a horizontal axis of the straight ahead iris image, and ahorizontal axis of the rolled head iris image, as applicable andappropriate.

The method 8000 includes when no match 8400, rejecting 8500 subject. Ifat least one of the straight ahead irises don't match, the straightahead irises have a rotation greater than the rotational variance, thehead rolled irises don't match, the head rolled irises have a rotationgreater than the rotational variance, then the subject fails and alertprocessing is performed.

The method 8000 includes for a first pass, when yes 8600, requesting8700 subject to perform head roll for a defined time 8800 and return toimage acquisition 8900, and for a second pass, when yes 8600 acceptsubject. A two level or stage iris check is performed for the subject. Astraight ahead position and when applicable, a head rolled position. Ifthe subject passes both, then the subject is approved or accepted.

FIG. 9 is a diagram of example method 9000 for detecting a weightedspoof contact lens in accordance with implementations of thisdisclosure. The method 9000 includes: requesting 9100 subject to roll ortilt head; acquiring 9200 iris images; establishing 9300 horizontal axisfor an iris image; matching 9400 irises to enrolled irises includingrotational variance; when no match 9500, rejecting 9600 subject; whenyes 9700, accepting 9800 subject. The method 9000 can be implementedusing at least one of the access control system 2400, the irisrecognition device 2410, the access control module 2420, the irisrecognition server 2430, the access control center 2440, the accesscontrol system 3000, the iris recognition device 3100, the accesscontrol module 3200, the iris recognition module 3110, the referencedatabase 3120, the detection module 3130, the one or more imagecapturing device(s) 3140, the one or more illuminator(s) 3150, thecontroller 3160, the iris enrollment system 3170, the iris recognitionserver 4000, the iris recognition module 4100, the reference database4200, the controller 4300, the iris enrollment system 4400, the irisrecognition module 5000, the eye finder module 5100 the iris findermodule 5200, the iris encoder module 5300, the iris matcher module 5400,the device 7000, the processor 7100, the memory/storage 7200, thecommunication interface 7300, and the applications 7400, for example.

The method 9000 includes requesting 9100 subject to roll or tilt head. Asubject is requested to roll their head a defined amount when requiringaccess.

The method 9000 includes acquiring 9200 iris images. Iris images arecaptured with the subject's head in a rolled position. Image(s) arecaptured immediately after the head roll and after a period of time. Theperiod of time provides the weighted contact lenses, if present, tosettle due to gravity. These images are processed as described hereinfor purposes of detecting weighted spoof contact lenses.

The method 9000 includes establishing 9300 horizontal axis for an irisimage. A horizontal axis is determined using the pupils in the irisimages.

The method 9000 includes matching 9400 irises to enrolled irisesincluding rotational variance. The head rolled irises are comparedagainst enrolled irises to determine an iris match. This includesdetermining whether the irises are within a rotational variance by usingthe horizontal axis.

The method 9000 includes when no match 9500, rejecting 9600 subject. Ifthe irises don't match, the irises have a rotation greater than arotational variance, or both, then the subject fails and alertprocessing is performed.

The method 9000 includes when yes 9700, accepting 9800 subject. If theirises match and the irises have a rotation equal or less than therotational variance, then the subject passes and access processing isperformed.

Although some embodiments herein refer to methods, it will beappreciated by one skilled in the art that they may also be embodied asa system or computer program product. Accordingly, aspects of thepresent invention may take the form of an entirely hardware embodiment,an entirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a “processor,”“device,” or “system.” Furthermore, aspects of the present invention maytake the form of a computer program product embodied in one or more thecomputer readable mediums having the computer readable program codeembodied thereon. Any combination of one or more computer readablemediums may be utilized. The computer readable medium may be a computerreadable signal medium or a computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer-readable storage medium include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a magnetic storage device, or any suitablecombination of the foregoing. In the context of this document, acomputer-readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electromagnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to CDs, DVDs,wireless, wireline, optical fiber cable, RF, etc., or any suitablecombination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions.

These computer program instructions may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer program instructions may also bestored in a computer readable medium that can direct a computer, otherprogrammable data processing apparatus, or other devices to function ina particular manner, such that the instructions stored in the computerreadable medium produce an article of manufacture including instructionswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowcharts and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures.

While the disclosure has been described in connection with certainembodiments, it is to be understood that the disclosure is not to belimited to the disclosed embodiments but, on the contrary, is intendedto cover various modifications, combinations, and equivalentarrangements included within the scope of the appended claims, whichscope is to be accorded the broadest interpretation so as to encompassall such modifications and equivalent structures as is permitted underthe law.

What is claimed is:
 1. A method for weighted spoof contact lensdetection, the method comprising: requesting a subject to roll or tilthead when needing access via an iris recognition device; acquiring, bythe iris recognition device, iris images of a rolled head; establishing,by the iris recognition device, a horizontal axis by connecting pupilsin an iris image; matching, by the iris recognition device, at least oneiris in the iris image to an enrolled iris; determining, by the irisrecognition device, whether the horizontal axis is within a rotationalvariance of an enrolled horizontal axis associated with the enrollediris; and rejecting, by the iris recognition device, access for thesubject when the horizontal axis is greater than the rotational varianceof the enrolled horizontal axis.
 2. The method of claim 1, wherein theacquiring iris images further comprising: waiting by the irisrecognition device, for a period of time after the head is rolled toacquire the iris images.
 3. The method of claim 1, further comprising:accepting, by the iris recognition device, the subject for accessprocessing when at least one iris matches the enrolled iris and thehorizontal axis is within the rotational variance of the enrolledhorizontal axis.
 4. The method of claim 1, further comprising:accepting, by the iris recognition device, the subject for accessprocessing when both irises match enrolled irises and each horizontalaxis is within the rotational variance of a respective enrolledhorizontal axis.
 5. The method of claim 1, further comprising:rejecting, by the iris recognition device, access for the subject wheneach horizontal axis is greater than the rotational variance of arespective enrolled horizontal axis.
 6. The method of claim 1, furthercomprising: rejecting, by the iris recognition device, access for thesubject when both irises fail to match enrolled irises.
 7. The method ofclaim 1, wherein the requesting is initiated by the iris recognitiondevice when at least one non-rolled head iris matches the enrolled irisand a non-rolled head horizontal axis is within a rotational variance ofthe enrolled horizontal axis.
 8. The method of claim 1, wherein therequesting is initiated by the iris recognition device when bothnon-rolled head irises match enrolled irises and a non-rolled headhorizontal axis is within a rotational variance of a respective enrolledhorizontal axis.
 9. The method of claim 8, wherein the determiningfurther comprising: determining, by the iris recognition device, whetherthe horizontal axis is within a rotational variance of the non-rolledhead horizontal axis.
 10. The method of claim 9, wherein the determiningfurther comprising: accepting, by the iris recognition device, thesubject for access processing when both irises match enrolled irises andthe horizontal axis is within the rotational variance of a respectiveenrolled horizontal axis and the horizontal axis is within therotational variance of a respective non-rolled head horizontal axis. 11.A method for weighted spoof contact lens detection, the methodcomprising: acquiring, by an iris recognition device, non-rolled headiris images of a subject needing access; establishing, by the irisrecognition device, a non-rolled head horizontal axis by connectingpupils in a non-rolled head iris image; matching, by the irisrecognition device, at least one iris in the non-rolled head iris imageto an enrolled iris; determining, by the iris recognition device,whether the non-rolled head horizontal axis is within a rotationalvariance of an enrolled horizontal axis associated with the enrollediris; acquiring, by an iris recognition device, rolled head iris imagesof the subject when the at least one iris in the non-rolled head irisimage matches the enrolled iris and the non-rolled head horizontal axisis within the rotational variance of a respective enrolled horizontalaxis; establishing, by the iris recognition device, a rolled headhorizontal axis by connecting pupils in a rolled head iris image;matching, by the iris recognition device, at least one iris in therolled head iris image to the enrolled iris; determining, by the irisrecognition device, at least one of whether the rolled head horizontalaxis is within the rotational variance of the enrolled horizontal axisor whether the rolled head horizontal axis is within the rotationalvariance of the non-rolled horizontal axis; and rejecting, by the irisrecognition device, access for the subject when at least one of therolled horizontal axis is greater than the rotational variance of theenrolled horizontal axis or the rolled horizontal axis is greater thanthe rotational variance of the non-rolled horizontal axis.
 12. Themethod of claim 11, wherein the rolled head iris images are acquired bythe iris recognition device after waiting a period of time after thehead is rolled.
 13. The method of claim 11, further comprising:accepting, by the iris recognition device, the subject for accessprocessing when at least one rolled head iris matches an enrolled irisand at least one of the rolled horizontal axis is within the rotationalvariance of the enrolled horizontal axis or the rolled horizontal axisis within the rotational variance of the non-rolled horizontal axis. 14.The method of claim 11, further comprising: accepting, by the irisrecognition device, the subject for access processing when both rolledhead irises match enrolled irises and at least one of the rolledhorizontal axis is within the rotational variance of a respectiveenrolled horizontal axis or the rolled horizontal axis is within therotational variance of a respective non-rolled horizontal axis.
 15. Themethod of claim 1, further comprising: rejecting, by the irisrecognition device, access for the subject when at least one of eachrolled horizontal axis is greater than the rotational variance of arespective enrolled horizontal axis or each rolled horizontal axis isgreater than the rotational variance of a respective non-rolledhorizontal axis.
 16. The method of claim 11, further comprising:rejecting, by the iris recognition device, access for the subject whenthe at least one iris in the non-rolled head iris image fails to matchthe enrolled iris.
 17. The method of claim 11, further comprising:rejecting, by the iris recognition device, access for the subject whenthe non-rolled head horizontal axis is greater than the rotationalvariance of the enrolled horizontal axis.
 18. An iris recognition devicecomprising: an image capture device configured to capture iris images ofa rolled head of a subject needing access via the iris recognitiondevice; an iris recognition module configured to: establish a horizontalaxis by connecting pupils in an iris image; match at least one iris inthe iris image to an enrolled iris; determine whether the horizontalaxis is within a rotational variance of an enrolled horizontal axisassociated with the enrolled iris; and reject access for the subjectwhen the horizontal axis is greater than the rotational variance of anenrolled horizontal axis.
 19. The iris recognition device of claim 18,wherein capturing of the iris images is done after waiting for a periodof time after the head is rolled.
 20. The iris recognition device ofclaim 18, the iris recognition module further configured to accept thesubject for access when at least one iris matches the enrolled iris andthe horizontal axis is within the rotational variance of a respectiveenrolled horizontal axis.
 21. A method for weighted spoof contact lensdetection, the method comprising: requesting a subject to roll or tilthead when needing access via an iris recognition device; acquiring, bythe iris recognition device, iris images of a rolled head; establishing,by the iris recognition device, a horizontal axis by connecting pupilsin an iris image; matching, by the iris recognition device, at least oneiris in the iris image to an enrolled iris; determining, by the irisrecognition device, whether the horizontal axis is within a rotationalvariance of an enrolled horizontal axis associated with the enrollediris or is within a rotational variance of a non-rolled horizontal axis;and rejecting, by the iris recognition device, access for the subjectwhen the horizontal axis is at least one of greater than the rotationalvariance of the enrolled horizontal axis or greater than the rotationalvariance of the non-rolled horizontal axis.